传粉昆虫物种多样性监测、评估和保护概述

欧洲和北美等国相继建立起传粉昆虫物种多样性监测和评估体系。基于传粉昆虫的监测资料,能够对欧美部分区域和某些传粉昆虫类群的现状、下降程度以及影响因素进行研究。欧洲和北美等地已开展部分传粉昆虫保护措施和项目,如欧洲部分国家实施的＂农田环境计划＂项目（Agri-Environmental Schemes）能够保护农田生态系统中传粉昆虫的栖境,恢复和提高传粉昆虫物种多样性。我国传粉昆虫物种多样性十分丰富,但目前还没有一个以监测和评估传粉昆虫物种多样性为主的平台,也未对某区域或某类群传粉昆虫多样性的变化进行评估,传粉昆虫多样性的保护也未引起足够重视。为了解我国传粉昆虫物种多样性现状及变化情况,作者建议在我国建立传粉昆虫物种多样性监测和评估体系,以提高我们在该领域的认识水平,并为开展相应的保护工作提供理论基础。     

不同钙离子浓度对低温下降香黄檀幼苗生长及生理特性的影响

以降香黄檀（Dalbergia odorifera T.Chen）为材料,通过人工控制温度的方法,探讨在不同温度条件下施加不同浓度Ca²⁺对降香黄檀幼苗生长及生理特性的影响。结果显示：常温条件下,施加不同浓度的Ca²⁺对降香黄檀的茎高、叶长、净光合速率（P_n）、气孔导度（G_s）、蒸腾速率（T_r）和光合色素含量均有显著影响;而对叶片相对含水量、露点水势、相对电导率、丙二醛（MDA）和可溶性蛋白含量影响较小;促进生长发育的最适Ca²⁺浓度为5 mmol/L。低温对降香黄檀上述生理指标以及水分利用效率（WUE）均有显著影响;低温条件下施加不同浓度的Ca²⁺能使上述指标得到不同程度的缓解,提高降香黄檀低温胁迫耐受性的最适浓度为5 mmol/L。隶属函数分析结果表明,常温和低温条件下,外源Ca²⁺浓度对降香黄檀的调控影响依次为5、10、15、2.5 mmol/L。     

Goodness-of-fit in generalized nonlinear mixed-effects models

In recent years, generalized linear and nonlinear mixed-effects models have proved to be powerful tools for the analysis of unbalanced longitudinal data. To date, much of the work has focused on various methods for estimating and comparing the parameters of mixed-effects models. Very little work has been done in the area of model selection and goodness-of-fit, particularly with respect to the assumed variance-covariance structure. In this paper, we present a goodness-of-fit statistic which can be used in a manner similar to the R2 criterion in linear regression for assessing the adequacy of an assumed mean and variance-covariance structure. In addition, we introduce an approximate pseudo-likelihood ratio test for testing the adequacy of the hypothesized convariance structure. These methods are illustrated and compared to the usual normal theory likelihood methods (Akaike's information criterion and the likelihood ratio test) using three examples. Simulation results indicate the pseudo-likelihood ratio test compares favorably with the standard normal theory likelihood ratio test, but both procedures are sensitive to departures from normality.     

Role of the mitochondrial signaling pathway in murine coronavirus-induced oligodendrocyte apoptosis

A previous study demonstrated that infection of rat oligodendrocytes by mouse hepatitis virus (MHV) resulted in apoptosis, which is caspase dependent (Y. Liu, Y. Cai, and X. Zhang, J. Virol. 77:11952-11963, 2003). Here we determined the involvement of the mitochondrial pathway in MHV-induced oligodendrocyte apoptosis. We found that caspase-9 activity was 12-fold higher in virus-infected cells than in mock-infected cells at 24 h postinfection (p.i.). Pretreatment of cells with a caspase-9 inhibitor completely blocked caspase-9 activation and partially inhibited the apoptosis mediated by MHV infection. Analyses of cytochrome c release further revealed an activation of the mitochondrial apoptotic pathway. Stable overexpression of the two antiapoptotic proteins Bcl-2 and Bcl-xL significantly, though only partially, blocked apoptosis, suggesting that activation of the mitochondrial pathway is partially responsible for the apoptosis. To identify upstream signals, we determined caspase-8 activity, cleavage of Bid, and expression of Bax and Bad by Western blotting. We found a drastic increase in caspase-8 activity and cleavage of Bid at 24 h p.i. in virus-infected cells, suggesting that Bid may serve as a messenger to relay the signals from caspase-8 to mitochondria. However, treatment with a caspase-8 inhibitor only slightly blocked cytochrome c release from the mitochondria. Furthermore, we found that Bax but not Bad was significantly increased at 12 h p.i. in cells infected with both live and UV-inactivated viruses and that Bax activation was partially blocked by treatment with the caspase-8 inhibitor. These results thus establish the involvement of the mitochondrial pathway in MHV-induced oligodendrocyte apoptosis.     

NF-kB 在哮喘病患儿支气管肺泡灌洗液中的表达及意义

目的:探讨NF-κB、IL-17在儿童支气管哮喘中的作用及机制。本文通过观察哮喘急性发作儿童支气管肺泡灌洗液(BALF)NF-κB、IL-17的水平变化,探讨其在哮喘急性发作儿童气道炎症中的作用。方法:我院2012年12月-2013年2月期间行纤维支气管镜检查患儿共80例,包括哮喘急性发作组(哮喘组,n=40)、非喘息组(肺炎组,n=20)及对照组(n=20),收集所有病例的BALF,进行细胞学分类,RT-PCR法测定BALF中细胞中NF-κB蛋白(P65mRNA)、IL-17mRNA的表达;Western法检测P65蛋白、IL-17蛋白表达。结果:与对照组比较,哮喘组和肺炎组患儿的P65mRNA、IL-17mRNA水平均明显增高;P65蛋白、IL-17蛋白水平均明显增高(均P<0.05);哮喘组患儿的P65mRNA、IL-17mRNA水平、P65蛋白、IL-17蛋白水平较肺炎组高(P<0.05)。结论:NF-κB、IL-17在哮喘儿童气道炎症中发挥重要作用,NF-κB通过调控IL-17来实现促进哮喘病情进展。     

表达EGFP报告基因口蹄疫病毒亚基因组复制子的构建

【目的】构建含有EGFP报告基因的口蹄疫病毒(FMDV)亚基因组复制子系统。【方法】利用融合PCR方法,将EGFP报告基因替换O型FMDV全长c DNA克隆中的前导蛋白Lb和结构蛋白P1基因,构建含有EGFP报告基因的FMDV亚基因组复制子FMDV-EGFP。复制子质粒连续转化、测序检验复制子载体的稳定性。Not I线性化的复制子FMDV-EGFP用脂质体介导法转染表达T7 RNA聚合酶的BSR/T7细胞后,不同时间段观察EGFP荧光表达情况。转染的细胞用流式、间接免疫荧光、RT-PCR和Western blot检测该复制子载体的自主复制能力和口蹄疫病毒蛋白的表达情况。【结果】复制子质粒的连续转化及测序表明报告基因可以稳定存在。FMDV-EGFP复制子转染BSR/T7细胞3 h后在荧光显微镜下能够看到绿色荧光,EGFP荧光信号随着转染时间的延长逐渐增加,并且荧光信号可持续6 d以上。转染24 h后的细胞流式分析显示转染的细胞中有6.0%发出荧光,说明构建的复制子载体能够有效表达EGFP蛋白。另外,间接免疫荧光、RT-PCR和Western blot方法也检测到该复制子RNA在BSR/T7细胞中能够进行自主复制,并且能够表达病毒的非结构蛋白。【结论】含有EGFP报告基因的FMDV亚基因组复制子的成功构建为进一步研究病毒复制、翻译机制及筛选抗病毒药物等奠定了坚实的基础。     

翠菊根系养分捕获形态塑性及其生理机制

为验证以下3个假设: 1) NO₃ ^-和NH₄ ⁺及其不同供给方式显著影响根系生长; 2) NO₃ ^-和NH₄ ⁺以及不同供给方式对根内激素含量影响显著; 3)根构型(1级根长、单位2级根上1级侧根密度(分枝强度)和1级根在2级根上的根间距)与根内激素(生长素(IAA)、脱落酸(ABA)和细胞分裂素(玉米素核苷+玉米素) (CK (ZR + Z))含量显著相关, 采用营养液培养方法, 使实验植物翠菊(Callistephus chinensis)在两种氮肥(NO₃ ^-和NH₄ ⁺)、不同施氮浓度(NO₃ ^-: 0.2、1.0和18.0 mmol·L ^-1; NH₄ ⁺: 0.2、4.0和20.0 mmol·L ^-1), 以及脉冲和稳定两种施用方式处理下生长。在处理35天后收获植物, 测定根系生物量、根系构型指标(根系1级根长、单位2级根上1级侧根数和1级根在2级根上的根间距)和根系中激素含量(IAA、ABA和CK (ZR + Z))。结果显示: 1)实验处理对根生物量和根系中IAA、ABA和CK (ZR + Z)含量均有不同程度的显著影响: 施用NH₄ ⁺使根生物量和根内IAA含量显著低于施用NO₃ ^-; 高浓度NO₃ ^-和NH₄ ⁺处理亦使根生物量和IAA降低; 相对于稳定处理, 脉冲施氮显著降低根生物量和根内IAA含量; NO₃ ^-使根内CK (ZR + Z)含量显著高于施用NH₄ ⁺, 且与施氮浓度及施氮方式无关; NO₃ ^-处理下, 高浓度使根内ABA含量提高, 且脉冲处理使ABA含量升高。NH₄ ⁺处理下, 高浓度使根内ABA含量降低, 而施氮方式对其没有显著影响。2)根构型因素与根内激素关系各异: 各激素与1级根间距无显著关系; IAA和CK (ZR + Z)与1级根长和侧根密度有显著回归关系。3)根构型因素与根生物量的关系是根生物量与1级根长和侧根密度有显著正回归关系, 与1级根间距无显著回归关系。实验结果表明翠菊根生长的 “反常”可能是由于其对脉冲高浓度NH₄ ⁺耐受阈值低所致。该研究通过实验建立了氮养分种类/供应方式通过改变激素、影响根构型而影响根生长的联系, 进一步探究了植物根养分捕获塑性机制。     

HCV Core Protein-Induced Down-Regulation of microRNA-152 Promoted Aberrant Proliferation by Regulating Wnt1 in HepG2 Cells

Background

Hepatitis C virus (HCV) has been reported to regulate cellular microRNAs (miRNAs). The HCV core protein is considered to be a potential oncoprotein in HCV-related hepatocellular carcinoma (HCV-HCC), but HCV core-regulated miRNAs are largely unknown. Our preliminary experiments revealed significant down-regulation of microRNA-152 (miR-152) by HCV core protein in HepG2 cells. Through target gene prediction softwares, Wnt1 was predicted to be a potential target of miR-152. The present study was initiated to investigate whether miR-152 is aberrantly regulated by the HCV core protein, and involved in the regulation of the aberrant proliferation of HCV-HCC cells.

Methods

MiR-152 levels were examined by stem-loop real-time RT-PCR (SLqRT-PCR). Cell proliferation was analyzed by MTT and colony formation assay. Cell cycle analysis was performed by flow cytometry. Luciferase reporter assay was conducted to confirm miRNA-target association. Wnt1 expression was determined by real-time qPCR and Western blotting.

Results

HCV core protein significantly suppressed miR-152 expression, and led to significant Wnt1 up-regulation with a concomitant aberrantly promoted proliferation. Moreover, we validated that miR-152 inhibition promoted, while miR-152 mimics inhibited cell proliferation. Using, qRT–PCR and western blot, Wnt1 was demonstrated to be regulated by miR-152. Luciferase activity assay showed that while miR-152 mimics significantly reduced the luciferase activity by 83.76% (P<0.0001), miR-152 inhibitor showed no effect on luciferase reporter. Most notably, salvage expression of miR-152 after Ad-HCV core infection for 24 h almost totally reversed the proliferation-promoting effect of the HCV core protein, and meanwhile, reduced the expression of both Wnt1 mRNA and protein to basal levels.

Conclusion

These findings provide important evidence that the reduced miR-152 expression by HCV core protein can indirectly lose an inhibitory effect on Wnt1, which might, at least partially lead to cell proliferation of liver cancer cells. MiR-152 may have a therapeutic potential to suppress liver cancer proliferation.